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板材单点增量成形夹具设计【含4张CAD图】
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充值购买-下载设计文档后，加 Q-1459919609 免费领取图纸I板材单点增量成形夹具设计摘要：单点增量成形作为一种新型板材柔性无模成形技术，其基于分层制造思想，通过工具头一层一层加工金属板料，柔性化程度高，利用局部变形实现金属板料零件的加工。和传统冲压成形相比，不需要专用设备和模具，能够缩短产品研发周期，降低产品研发成本，特别适用于多品种、小批量以及个性化生产，在汽车、船舶、家电、航天航空等领域有广泛的应用前景。当前单点增量成形过程中一般采用上下压板和螺栓对板料进行夹持，其过程需要人工辅助，严重影响加工效率，为了解决这一问题，需要设计一种具有自动压紧定位功能的新型板材单点增量成形夹具。论文采用有限元仿真和实验相结合的方法，得到单点增量成形过程中各向变形力的变化规律，对其成形角、层间距、板料厚度及工具头直径对变形力的影响进行研究，得到不同工艺参数下成形过程的最大变形力；根据得到的最大变形力选择成形夹具的压板尺寸和压紧方式，分别利用 AutoCAD 和 Solidworks软件进行成形夹具的二维和三维设计，并对夹具的可行性进行三维动画模拟，最终得到一种可以大幅度提高装夹效率的成形夹具。关键词：单点增量成形；数值分析与建模；变形力；夹具设计；充值购买-下载设计文档后，加 Q-1459919609 免费领取图纸IIAbstract：Single point incremental forming is a new type of sheet metal flexible dieless forming technology. Based on the idea of layered manufacturing, the metal sheet is processed one layer at a time through the tool head. The degree of flexibility is high, and the metal sheet part is realized by local deformation. Processing. Compared with traditional press forming, it does not require special equipment and molds, which can shorten the product development cycle and reduce the cost of product development. It is especially applicable to many varieties, small batches, and individualized production. It has applications in automobiles, ships, home appliances, aerospace and other fields. Wide application prospects. In the current single-point incremental forming process, upper and lower press plates and bolts are generally used to clamp the sheet material, and the process needs manual assistance, which seriously affects the processing efficiency. To solve this problem, a new type of automatic pressing and positioning function needs to be designed. Sheet single point incremental forming fixture.In this paper, finite element simulation and experimental methods are used to obtain the variation law of the isotropic deformation force in the single-point incremental forming process. The effects of forming angle, layer spacing, sheet thickness, and tool head diameter on the deformation force are studied. The maximum deformation force of the forming process under different process parameters is obtained; the platen size and compression method of the forming fixture are selected according to the obtained maximum deformation force, and the two-dimensional and three-dimensional design of the forming fixture are respectively performed using AutoCAD and Solidworks software, and the fixture is The feasibility of three-dimensional animation simulation, and ultimately get a fixture can greatly increase the clamping efficiency.充值购买-下载设计文档后，加 Q-1459919609 免费领取图纸IIIKeywords: single point incremental forming; numerical analysis and modeling; deformation force; fixture design;充值购买-下载设计文档后，加 Q-1459919609 免费领取图纸IV目 录摘要 .IAbstract： .II1 绪 论 .11.1 单点增量成形的原理 .11.2 单点增量成形的国内外研究现状 .21.3 本文研究主要内容 .32 单点增量成形过程变形力分析 .52.1 单点增量成形变形力理论解析 .52.2 单点增量成形变形力数值模拟 .82.2.1 有限元数值模拟参数设定 .82.2.2 变形力模拟结果 .122.2.3 工艺参数对变形力的影响 .143 单点增量成形过程变形力实验研究 .193.1 实验设备介绍 .193.2 基于 UG 的 NC 代码生成 .203.2.1 成形件实体建模 .213.2.2 单点增量成形过程加工轨迹的生成 .213.2.3 后处理 NC 程序的生成 .233.3 实验结果和模型验证 .234 单点增量成形夹具设计 .27结 论 .32致 谢 .33参 考 文 献 .34附录外文文献及翻译 .36外文文献 .36Formability in single point incremental forming: A comparative analysis of the state of the art.36中文翻译 .41单点增量成形过程中成形性的研究现状 .41充值购买-下载设计文档后，加 Q-1459919609 免费领取图纸11 绪 论1.1 单点增量成形的原理随着加工制造业的发展需求，传统的制造方式也发生着改变。金属板料的加工从有模成形变化到无模柔性，这些都是适应现代制造业柔性，绿色等要求特点而发展起来的金属板料的成形技术。现已经出现的板料柔性成形技术主要有：单点增量成形、多点无模成形、激光热应力成形、旋压成形、喷丸成形等1。上述无模成形技术都是借助数控机床来实现对金属板料的无模柔性加工，克服了传统成形技术依靠模具成形的不足，对新产品的研发试制及小批量个性化的产品生产有非常重要的意义2。上世纪 90 年代初，日本学者松原茂夫提出一种新型的金属板料成形方法，即板料单点增量成形技术。通过计算机辅助制造与数控机床相结合的方法，通过 CAD/CAM 辅助制造技术完成待加工产品模型的建立，生成的 NC 代码结合高精度数控机床的运行来实现3-4，其成形原理如图 1-1 所示。因为 CAD/CAM 技术的发展，可以完成较复杂的模型加工，现代数控机床加工精度的提高，使得复杂建模得以在数控机床上实现。该技术在板料成形时不需要专用模具或仅需要简单的支撑工具，其所需的成行力小，适合零件的试制及小批量生产，满足了市场对产品的多样化和个性化需求。鉴于数控单点增量成形技术的优点，国内外学者已经开始关注这种兴起的先进柔性塑性成形技术，并对它进行了很多研究工作并取得大量的研究成果。工 具 头上 压 板板 料下 压 板图 1-1 单点增量成形原理充值购买-下载设计文档后，加 Q-1459919609 免费领取图纸21.2 单点增量成形的国内外研究现状金属板料单点增量成形技术自提出以来，也受到了国内学者的关注，并取得了喜人的成就。从板料拉伸减薄的角度分析，得出成形过程属于变薄拉延类型5；并通过计算分析及实验验证方法得出变形力的计算公式6 。从成形性能分析，南京航空航天大学的崔震，高霖等7，采用数控单点渐进成形技术对钣金浮雕字进行了成形研究，完成了高质量钣金浮雕字的成形。到目前对板料增量成形技术的分析工作取得一些进展，对板料变形过程中各部位材料的变形情况及各参数下的成形性能进行研究，对于提高产品的成形质量、工艺的制定以及推广有重要的理论意义和工程应用价值。单点增量成形过程中的成形力研究是研究单点增量成形的重要组成部分，单点增量成形是通过工具头与板料的相互挤压，局部成形累积到整体成形，成形过程中，成形力的大小将决定板料是否发生破裂，而且可以计算成形过程的能量转换与损耗。在研究工具头高速自转下板料升温现象中，Bagudanch 等8对工具头自转速度、工具头直径与成形力间的关系进行了研究。通过对金属板料成形破裂的研究，Gabriel Centeno 等9 分析了工具头转速和 T/R 对成形力的影响。Belchior 等10 通过有限元软件建立的金属板料弹性模型，分析了成形力对机器人成形板料过程中误差补偿的影响。Martins 等11 在研究摩擦力对成形过程的影响中，通过应力解释了板料破裂和其局部颈缩的现象。Duflou 等12通过对金属板料进行局部加热，使得金属板料塑性提高，成形力降低，回弹减少。Eyckens 等13 在单点增量成形中使用不同的润滑剂对加工过程润滑，分析研究了轴向力和切向力在不同摩擦系数下的变化情况。Durante 等14使用有限元仿真软件验证了实验中工具头转速对摩擦系数的影响，进而分析出不同转速对于成形力的影响。Henrard 等15 使用有限元仿真软件验证了实验中不同成形角对成形力的影响。Aerens16等分析计算出成形力预测的经验公式，通过对稳态下轴向力的计算，验证了此公式的正确性。板料单点增量成形的过程涉及到了物理、材料、高等数学、机械等多个学科，以及复杂的力学方面知识，运用理论计算成形过程中的应力场和应变场是非常艰巨的，预测成形过程中的各种变形也需要大量的实验研究，这必然导致了实验成本的大量提升17-20。随着计算机的发展，数值分析对学术研究非常重要，许多学者研究了板料单点渐进成形过程中的数值分析。C. Bouffioux21-22等使用实体单元对成形过程使用有限元的模拟，通过实验的对比从而验证了数值充值购买-下载设计文档后，加 Q-1459919609 免费领取图纸3分析的正确性，并且分析了不同成形角对成形力造成的影响，得出了结论：成形角越大，成形力越大。国内学者李湘吉23等运用有限元的方法对板料成形过程进行了数值模拟，分析了成形过程中应力分布和壁厚的变化趋势，分析了不同参数对成形过程中造成的影响，指出金字塔形工件的最大应力和最大厚度减薄都会发生在拐角处，在成形过程中，螺旋线运动轨迹可以提高板料的成形的能力和成形的质量。胡建标24使用 ABAQUS/Explicit 有限软件建立了圆锥台仿真模型，分析了半顶角、层间距、工具头直径等参数在成形过程中对板料壁厚和成形质量的影响。本课题有限元数值仿真和实验研究相结合的方法，研究成形过程的变形力，根据得到的变形力进行夹具设计，以期得到一种操作方便、结构简单的单点增量成形板料自动夹持装置。 1.3 本文研究主要内容利用理论计算、有限元数值仿真和成形实验相结合的方法，研究工艺参数（成形角、层间距、板料厚度及工具头直径）对变形力的影响规律，得到成形过程中的最大变形力，根据得到的变形力选择合适的上下压板形式和夹紧方式，设计出满足最大变形力要求的成形夹具，利用二维绘图软件 AutoCAD 和三维绘图软件 Solidworks 绘制所设计夹具的二维和三维图，并且再对夹具的可行性进行三维动画的模拟。具体的研究内容如下：（1）板材单点增量成形过程变形力的理论研究 阅读相关资料，了解板料单点增量成形原理，分析成形过程材料变形特点，建立单点增量成形过程产生变形力的模型，最后对变形力进行分析。 （2）板材单点增量成形数值进行建模与分析 利用数值分析软件 ABAQUS 建立单点增量成形的有限元模型，以圆锥台件为例得到成形过程中变形力的变化规律，并通过研究成形角、层间距、板料厚度和工具头直径对变形力的影响规律，得到给定工艺范围内的最大变形力。 （3）板材成形实验的研究 通过数控铣床来搭建增量成形的平台，编写圆锥台件的数控加工代码，利用三向测力仪得到变形过程的变形力，和仿真结果进行对比，对所建立模型进行验证。 （4）成形夹具的设计充值购买-下载设计文档后，加 Q-1459919609 免费领取图纸4根据已得到的最大变形力，利用二维绘图软件 AutoCAD 和三维绘图软件Solidworks 绘制所设计夹具的二维和三维图，用三维动画模拟夹具的可行性。充值购买-下载设计文档后，加 Q-1459919609 免费领取图纸52 单点增量成形过程变形力分析2.1 单点增量成形变形力理论解析为简化分析计算，假设单点增量成形过程中板料单元进行纯剪切变化，如图 2-1 所示， z 是沿板料壁向 ce 面的拉应力， x 是剪切面 cd 面所受的径向应力， 0 是作用于剪切面 cd 面的剪应力，板料三角变形区域受力情况如下：图 2-1 单点增量成形区域应力分析示意图由于沿壁向合力为 0，故力平衡方程为： 0(sin)(cos)0zeccdxcdSSScos,ecdSa将 代 入 上 式 得 00taxz由于垂直于成形面的合力为 0，故在该方向的力平衡方程为：0 0(cos)(sin)cotxcdxcdaSaSa， 即0otanz联 立 以 上 两 式 ， 可 得 ： 单点增量负成形和正成形受力情况完全相同，为简明表达各成形分力间的几何关系，简化变形力的计算，在分析变形力几何关系时统一采用正成形模型，如图 2-2 和图 2-3 所示。充值购买-下载设计文档后，加 Q-1459919609 免费领取图纸6图 2-2 单点增量变形力分解示意图板料变形过程中各单元体的厚度取为 dx，工具头下压层间距为 Z，则单元体切应变 可如下求得： =tanZdx则单元材料的塑性变形功为： tan000xWWd ， 可 改 写 为 由 变 形 能 量 守 恒 可 得 ， 等 效 应 与 切 应 变 的变 关 系 为 ：1tan3取圆锥台成形件某一高度的截面半径为 Rc，变形区域宽度为 dRc，工具头半径为 R，成形角为 ，如图 2-5 中几何关系可求得该加工层板料变形体积为：2(cotsin)cVRtdZaR则该层的体积变能为： 1 0(tsi)CWd切向力在加工该层所做的功为： 2cyRF由于是纯剪切变形，故 W1=W2，联立以上两试： 0(otsin)yFZ根据 Mises 屈服准则，可将上式简化为： (ctsi)y sR附录外文文献及翻译外文文献Formability in single point incremental forming: A comparative analysis of the state of the artSingle point incremental forming (SPIF) is a method of manufacturing components from sheets of material, with the advantage of little to no customised tooling and otherwise generic setup 1. This makes it ideal for producing sheet metal prototype components before investing in a stamping mould, or for one-off customised components.SPIF is a type of incremental sheet forming (ISF), a class of processes which includes spinning and shear forming 2. SPIF has the advantage over a method such as spinning of being able to form asymmetric shapes. In the 2005 paper, Jeswiet et al. 3 succeeded in bringing all the current knowledge at that time and synthesising it into a comprehensive review of the progress and state of the art of asymmetric ISF processes. The decade of research since then calls for an updated review of the progress and understanding of SPIF, including incremental forming of polymer sheets rst explored in 2008 4.This paper comprises a review of literature on single point incremental forming, specically to present the process param- eters that inuence the formability of the material during forming. Organising the results of this investigation will assist in creating straightforward parameter guidelines and instructions useful for future research and manufacturing real components with SPIF.While commercial and industrial SPIF components have been made in the past, they can be so complex that trial and error becomes the most feasible development technique, as using FEA (nite element analysis) would be too computationally expensive. Therefore, a signicant challenge is how to develop it into an industrial process using methods more sophisticated than trial and error.The aim of this literature review is to collect relevant data from experimental papers and draw conclusions on maximising the formability of the material used in SPIF. The other aspects of SPIF that are not systematically covered in this review are forming forces, surface quality, geometric accuracy, and resultant material properties.Formability is most commonly quantied by nding the maximum wall angle (Fmax) to which the material can be formed before failure occurs 5, with respect to the horizontal plane.Typically a simple shape, such as a cone or pyramid, is used to determine this maximum wall angle. Multiple parts can be formed, each one with a steeper wall angle than the previous, until a part breaks 6.Another option is a shape where the wall angle changes from shallow to steep, for example the variable wall angle conical frustum (VWACF) reported in 2007 by Hussain et al. 7. If this part is used, only one test is needed to determine the wall angle where failure occurs. In the same paper, Hussain et al. 7 compared the VWACF results and results from straight-wall tests and found the latter overestimated Fmax by less than 4% due to its higherstiffness. Therefore, if the exact wall angle at fracture is required for straight wall parts, the VWACF results should be further tested with conical or pyramidal frustums. Any formability test, however, if it is repeated accurately, should give consistent results such that the general effect of a process parameter can be determined. The general effect, further explained in Results and discussion section, provides the data that is analysed in this literature review.Many different materials have been used in SPIF, including a variety of metals 3, polymer sheets 4, and other sheet materials such as sandwich panels 8, with a wide range of formability among them. This review will not examine formability limits of specic materials but will instead list them in the parameter analyses to allow comparison between experiments with the same material, for example PVC or AA3003-O. Material type can be seen as the base upon which all other parameters are selected.The thickness of the undeformed material blank is an important parameter and has signicant effects on the SPIF process and nal part, especially the force needed to deform the sheet which increases with increasing thickness 9. Sheet thickness is also a factor in the sine law equation for shear forming, where the nalthickness (tf) of a part can be calculated from the initial thickness (ti) and the wall angle from horizontal (F). The equation is tf = ti * sin(90 F) and has been shown to be accurate for SPIF parts formed in a single pass 10.The absolute values of thickness are not important in this review, as unique material properties mean a 2 mm sheet of one material performs differently to a 2 mm sheet of a different material 3. Only the general effect of increasing or decreasing the thickness of the undeformed blank has been studied.Tool parameters The tool or punch used in SPIF to deform the sheet has traditionally been one of two types. Firstly, a solid hemispherical tool 2, and secondly, a tool with a ball bearing in a socket, allowing it to roll freely over the sheet 6. As progress in SPIF and incremental forming in general developed, the types of tools expanded to include at-ended and other shaped tools 11. Fig. 1 shows the dimensions used to describe 3 main types of tools. Theadvantages of one type of tool over another have been a consistent area of research for some time, for example Kim and Park 12 and more recently Cawley et al. 13. Tool diameter and tool type are two parameters studied in this literature review.The size and end-shape of the tool inuence the mechanisms of the forming process. The size and shape of the area of contact between the tool and sheet can affect process aspects such as generated friction 14, observed forces 15, and pressure 16.The tools can be made from different materials, and the interaction between the tool material, blank material and lubrica- tion inuence the friction conditions seen during the process 17. Currently there have been no published journal papers examining the effect of different tool materials on formability in SPIF, therefore it is not able to be included in this literature review.Toolpath parameters The toolpath used in SPIF can be the equivalent of a machining operation such as Z-level nishing, though the tool does not cut the material. The motion of the tool is dened by the same parameters used in machining operations. Feed rate is the velocity of the tool as it moves over the sheet, typically dened in mm/min. Step down is how far the tool presses into the sheet with each circuit. Spindle speed is how fast the tool spins, specied in rotations per minute (rpm).Toolpath parameters inuence the generated friction by the movement and rotation of the tool 18, and the feed rate and step down dene the deformation rate of the material.The relative rotation directions of the tool and toolpath determine the milling mode; either conventional or climb milling, to use the standard machining terms. If the tool and the toolpath are both moving clockwise or counterclockwise, it is conventional milling, and if they are rotating in different directions, it is climb milling. Climb milling is the most commonly used mode in SPIF, as the friction is reduced by the tool effectively rolling over the sheet as it forms 19. While cutting tools typically rotate in a clockwise direction, and therefore specifying toolpath direction might be enough for the reader to assume which milling mode is being used, it is not as thorough as dening conventional or climb (rolling) milling as the utilised machining mode.Geometry The shape of the incrementally formed part affects the strains and therefore the formability of the material. The geometry is an aspect which is not covered in this literature review due to the complexity of analysing the many different shapes and dimensions used across the studied papers.In manufacturing a practical component, a draft angle analysis can be performed on the CAD model of the part to highlight which walls are steeper than a specied angle. Using the maximum wall angle for that material in the analysis will show whether there are any sections which may be too steep to form in a single SPIF pass. If there are no sections steeper than the permitted angle, it is likely that the part will succeed 20. The curvature of the part, from straight walls to tight curves, affects the types of strains (plane, biaxial) developed during the process. For example strains from a conical frustum with 100 mm radius compared to the edge of a pyramidal frustum with 10 mm radius, as presented in Filice et al.Since the process was rst developed, research has been conducted into modications of the basic SPIF process. For example, many different methods of heating the workpiece havebeen explored. Duou et al. 23 in 2007 used a laser to improve Fmax of TiAl6V4 sheets by more than 208. The same Titanium alloy was heated up to 400 8C with band heaters installed in the blankholder in Palumbo and Brandizzi 24, and an improvement in formability was observed. The use of electric current through the tool and the sheet has been explored in recent years, also applied to TiAl6V4 25 and other materials such as AA6061-T6 26 with resulting formability improvements. As this literature review studies process parameters for basic SPIF, parameters relevant to hot SPIF and electric SPIF are not examined.This work Research question What does the literature say about the effects of SPIF process parameters on formability?Hypothesis Each parameter has an optimal operating range which is a function of other parameters. They are interdependent in various combinations.This literature review is undertaken as a systematic quantita- tive literature review. This type of literature review is dened in Pickering and Byrne 27. The process has been tested by multiple students and researchers, and produces repeatable and high quality results.This technique is highly applicable to the area of SPIF parameters due to the quantitative nature of the data input, and as will be seen in the tabulated results, allows effective comparisons of parameter values between multiple papers. The selected parameters that have been studied in this review are universal to every single pass SPIF process, and more specialised processes such as applying electric current or external heat are not addressed.Many SPIF papers have been published in the area of formability, however the inclusion criteria highlighted below are used to select a high quality collection of papers that are a good representation of the wider eld.Details of the process steps as they relate to this literature review are shown below. Formability in single point incremental forming. 中文翻译单点增量成形过程中成形性的研究现状单点增量成形（SPIF）是一种用片材制造零件的方法，具有很少或没有定制工具和其他通用装置的优点1。 这使其成为在投资冲压模具或一次性定制部件之前生产钣金原型部件的理想选择。SPIF 是一种增量成型（ISF） ，这是一类包括旋压和剪切成型的工艺2。 SPIF 比诸如能够形成不对称形状的旋转方法具有优势。 在 2005 年的论文中，Jeswiet 等人 3成功地将当时所有的知识综合起来，并将其综合成为对不对称ISF 过程的进展和现状进行综合评述。 自那时起的十年研究要求对 SPIF 的进展和理解进行更新审查，包括 2008 年首次探索的增量成形聚合物片4。本文包括对单点增量成形的文献进行回顾，特别介绍影响成形过程中材料成形性的工艺参数。 组织调查结果将有助于创建直观的参数指南和说明，以便将来用 SPIF 研究和制造真实组件。虽然商业和工业 SPIF 组件过去已经制造出来，但它们可能非常复杂，以至于“试错”成为最可行的开发技术，因为使用 FEA（有限元分析）的计算过于昂贵。 因此，一个重大挑战是如何使用比试验和错误更复杂的方法将其发展成为工业过程。这篇文献综述的目的是收集实验论文的相关数据并得出最大化 SPIF 材料成形性的结论。 SPIF 的其他方面未在本文中进行系统的介绍，它们正在形成力量，表面质量，几何精度以及由此产生的材料属性。成形性通常通过找出材料在失效前形成的最大壁角（Fmax）5 与水平面之间的关系进行量化。通常使用简单的形状，例如圆锥或金字塔来确定该最大壁角。可以形成多个部件，每个部件都具有比先前更陡的壁角，直到部件断裂6。另一种选择是壁角从浅到陡变化的形状，例如 Hussain 等人 2007 年报道的可变壁角圆锥截头体（VWACF） 。 7。如果使用这部分，只需要一个测试来确定发生故障的墙角。在同一篇论文中，Hussain et al。 7比较了 VWACF 的结果和直墙试验的结果，发现后者高估了 Fmax 由于其较高的天气而低于 4。因此，如果直壁部分需要确切的骨折壁角度，则 VWACF 结果应进一步用锥形或锥形平截头体进行测试。任何可成型性测试，但是，如果重复准确，应该给出一致的结果，以便可以确定过程参数的一般影响。 “结果与讨论”一节中进一步解释了总体效应，该文献提供了该文献综述中分析的数据。在 SPIF 中已经使用了许多不同的材料，包括各种金属3，聚合物片材4 和其他片材材料，如夹层板8 ，其中具有广泛的可成形性。该评论不会检查特定材料的成形性限制，而是将其列入参数分析中，以便可以在相同材料（例如PVC
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